Prostacyclin production by human endothelial and bovine smooth muscle cells in culture. Effect of repeated stimulation with arachidonic acid, thrombin and ionophore A23187

Prostacyclin (prostaglandin I2) is the major product of arachidonic acid metabolism in vascular cells. Its physiological role may be linked to the ability of the cells to respond continuously with prostaglandin I2 production to a variety of stimuli. We report that human endothelial cells or bovine smooth muscle cells in culture respond with prostaglandin I2 synthesis to a first but not to a second stimulation with arachidonic acid. The development of this refractoriness was independent of the arachidonic acid concentration used (6.6-25 microM) and lasted for about 6 h. The same time was required for the cells to recover completely after inhibition of cyclooxygenase activity by aspirin. Neither cis-polyunsaturated fatty acids (linoleic or oleic acids) nor stearic acid (a long-chain saturated fatty acid) prevented the generation of prostaglandin I2 by arachidonic acid. Similarly to arachidonic acid, thrombin and ionophore A23187 could elicit vascular prostaglandin I2 synthesis only once. Pretreatment of the cells with arachidonic acid rendered the cells unresponsive to any other stimulus. These results indicate that the mechanism of the refractoriness induced by arachidonic acid was different from that induced by the other stimuli. It is proposed that vascular cells cannot be stimulated continuously to produce prostaglandin I2, but this process is regulated by different feedback mechanisms.     

Chromosome endoreduplication in endosperm cells of two maize genotypes and their progenies

Summary Chromosome endoreduplication is a very common process in higher plants but its function and genetic control are still to be clarified. In our experiments we analyzed, by Feulgen cytophotometry, chromosome endoreduplication in endosperm cells of two maize genotypes, IHP and ILP, having high and low protein content in their seed, respectively. Chromosome endoreduplication occurs in both lines within 24 days after pollination, attaining a maximum ploidy level of 384C (7 DNA replication rounds) in IHP and of 192C (6 replication rounds) in ILP. In the mature seed, endosperms of the two lines show different mean ploidy level. In reciprocal crosses between IHP and ILP the f₁ endosperms have mean ploidy levels analogous to that of the maternal parent, showing that the difference in ploidy level between the two genotypes is maintained. After selfing of the f₁ plants, the difference in ploidy level between the two F₂ populations is reduced. In F₂ the mean ploidy level is as variable as in f₁, indicating the absence of genetic segregation. From our data, it is apparent that both the genetic constitution (cytoplasmic and nuclear) of the maternal parent and the genotype of the individual endosperms influence the ploidy level. An analysis of the protein content in endosperms carried out on the same seed sample as analyzed cytophotometrically showed that the protein content increases, during seed development, parallel to chromosome endoreduplication and varies, in the two lines, in reciprocal crosses and their progeny, according to the same trend as mean ploidy level, suggesting a correlation between the two parameters.     

A scoping review of burden of disease studies estimating disability-adjusted life years due to Taenia solium

BackgroundTaenia solium is the most significant global foodborne parasite and the leading cause of preventable human epilepsy in low and middle-income countries in the form of neurocysticercosis.ObjectivesThis scoping review aimed to examine the methodology of peer-reviewed studies that estimate the burden of T. solium using disability-adjusted life years.Eligibility criteriaStudies must have calculated disability-adjusted life years relating to T. solium.Charting methodsThe review process was managed by a single reviewer using Rayyan. Published data relating to disease models, data sources, disability-adjusted life years, sensitivity, uncertainty, missing data, and key limitations were collected.Results15 studies were included for review, with seven global and eight national or sub-national estimates. Studies primarily employed attributional disease models that relied on measuring the occurrence of epilepsy before applying an attributable fraction to estimate the occurrence of neurocysticercosis-associated epilepsy. This method relies heavily on the extrapolation of observational studies across populations and time periods; however, it is currently required due to the difficulties in diagnosing neurocysticercosis. Studies discussed that a lack of data was a key limitation and their results likely underestimate the true burden of T. solium. Methods to calculate disability-adjusted life years varied across studies with differences in approaches to time discounting, age weighting, years of life lost, and years of life lived with disability. Such differences limit the ability to compare estimates between studies.ConclusionsThis review illustrates the complexities associated with T. solium burden of disease studies and highlights the potential need for a burden of disease reporting framework. The burden of T. solium is likely underestimated due to the challenges in diagnosing neurocysticercosis and a lack of available data. Advancement in diagnostics, further observational studies, and new approaches to parameterising disease models are required if estimates are to improve.     

Dynamic changes in microbiota and mycobiota during spontaneous ‘Vino Santo Trentino’ fermentation

Vino Santo is a sweet wine produced from late harvesting and pressing of Nosiola grapes in a small, well‐defined geographical area in the Italian Alps. We used metagenomics to characterize the dynamics of microbial communities in the products of three wineries, resulting from spontaneous fermentation with almost the same timing and procedure. Comparing fermentation dynamics and grape microbial composition, we show a rapid increase in a small number of wine yeast species, with a parallel decrease in complexity. Despite the application of similar protocols, slight changes in the procedures led to significant differences in the microbiota in the three cases of fermentation: (i) fungal content of the must varied significantly in the different wineries, (ii) Pichia membranifaciens persisted in only one of the wineries, (iii) one fermentation was characterized by the balanced presence of Saccharomyces cerevisiae and Hanseniaspora osmophila during the later phases. We suggest the existence of a highly winery‐specific ‘microbial‐terroir’ contributing significantly to the final product rather than a regional ‘terroir’. Analysis of changes in abundance during fermentation showed evident correlations between different species, suggesting that fermentation is the result of a continuum of interaction between different species and physical–chemical parameters.     

Computational evaluation of load carriage effects on gait balance stability

Evaluating the effects of load carriage on gait balance stability is important in various applications. However, their quantification has not been rigorously addressed in the current literature, partially due to the lack of relevant computational indices. The novel Dynamic Gait Measure (DGM) characterizes gait balance stability by quantifying the relative effects of inertia in terms of zero-moment point, ground projection of center of mass, and time-varying foot support region. In this study, the DGM is formulated in terms of the gait parameters that explicitly reflect the gait strategy of a given walking pattern and is used for computational evaluation of the distinct balance stability of loaded walking. The observed gait adaptations caused by load carriage (decreased single support duration, inertia effects, and step length) result in decreased DGM values (p < 0.0001), which indicate that loaded walking motions are more statically stable compared with the unloaded normal walking. Comparison of the DGM with other common gait stability indices (the maximum Floquet multiplier and the margin of stability) validates the unique characterization capability of the DGM, which is consistently informative of the presence of the added load.     

Neocortical Expansion Due to Increased Proliferation of Basal Progenitors Is Linked to Changes in Their Morphology

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Radiobiology of stereotactic radiotherapy

This paper focuses on the radiobiological mechanisms underlying the effects of stereotactic radiotherapy (SRT ) which, despite SRT expansion, have not yet been fully elucidated. Some authors postulated that radiobiology principles, as applied to conventional fractionations (5R: reoxygenation, repair, repopulation, redistribution, radioresistence), suffice in themselves to account for the excellent clinical results of SRT; others argued that the role of the 5R was limited. Recent preclinical data showed that hypofractionated ablative treatments altered the microenvironment, thus determining cell death either directly or indirectly. Furthermore, dead tumor cells released quantities of antigens, which stimulated antitumor immunity, thus reducing the risk of relapse and metastasis. Better understanding of the radiobiological mechanisms underlying response to high-dose radiation treatment is essential for predicting its short- and long-term effects on the tumor and surrounding healthy tissues and, consequently, for improving its related therapeutic index.     

A dual approach in the study of poly (ADP-ribose) polymerase: In vitro random mutagenesis and generation of deficient mice

A dual approach to the study of poly (ADP-ribose)polymerase (PARP) in terms of its structure and function has been developed in our laboratory. Random mutagenesis of the DNA binding domain and catalytic domain of the human PARP, has allowed us to identify residues that are crucial for its enzymatic activity.In parallel PARP knock-out mice were generated by inactivation of both alleles by gene targeting. We showed that: (i) they are exquisitely sensitive to -irradiation, (ii) they died rapidly from acute radiation toxicity to the small intestine, (iii) they displayed a high genomic instability to -irradiation and MNU injection and, (iv) bone marrow cells rapidly underwent apoptosis following MNU treatment, demonstrating that PARP is a survival factor playing an essential and positive role during DNA damage recovery and survival.